function code_draw() {
    var canvas_width = $('#canvas').width();
    var canvas_height = $('#canvas').height();
    var canvas = document.getElementById("canvas"); //鑾峰彇鍒癱anvas鐨勫璞★紝婕斿憳
    var context = canvas.getContext("2d"); //鑾峰彇鍒癱anvas鐢诲浘鐨勭幆澧冿紝婕斿憳琛ㄦ紨鐨勮垶鍙�
    canvas.width = canvas_width;
    canvas.height = canvas_height;
    var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0"; //鍙栧€艰寖鍥�
    var aCode = sCode.split(",");
    var aLength = aCode.length; //鑾峰彇鍒版暟缁勭殑闀垮害
    var value = [];
    for (var i = 0; i <= 3; i++) {
        var j = Math.floor(Math.random() * aLength); //鑾峰彇鍒伴殢鏈虹殑绱㈠紩鍊�
        var deg = Math.random() * 30 * Math.PI / 180; //浜х敓0~30涔嬮棿鐨勯殢鏈哄姬搴�
        var txt = aCode[j]; //寰楀埌闅忔満鐨勪竴涓唴瀹�
        value[i] = txt.toLowerCase();
        var x = 10 + i * 20; //鏂囧瓧鍦╟anvas涓婄殑x鍧愭爣
        var y = 20 + Math.random() * 8; //鏂囧瓧鍦╟anvas涓婄殑y鍧愭爣
        context.font = "bold 23px 寰蒋闆呴粦";

        context.translate(x, y);
        context.rotate(deg);

        context.fillStyle = code_randomColor();
        context.fillText(txt, 0, 0);

        context.rotate(-deg);
        context.translate(-x, -y);
    }
    // 灏嗙敓鎴愮殑鍊间互灞炴€х殑鏂规硶娣诲姞鍒板厓绱�
    value = value.join("");
    $('#canvas').attr('data-code', value)
        //楠岃瘉鐮佷笂鏄剧ず绾挎潯
    for (var i = 0; i <= 5; i++) {
        context.strokeStyle = code_randomColor();
        context.beginPath();
        context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
        context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
        context.stroke();
    }
    //楠岃瘉鐮佷笂鏄剧ず灏忕偣
    for (var i = 0; i <= 30; i++) {
        context.strokeStyle = code_randomColor();
        context.beginPath();
        var x = Math.random() * canvas_width;
        var y = Math.random() * canvas_height;
        context.moveTo(x, y);
        context.lineTo(x + 1, y + 1);
        context.stroke();
    }
}

function code_randomColor() { //寰楀埌闅忔満鐨勯鑹插€�
    var r = Math.floor(Math.random() * 256);
    var g = Math.floor(Math.random() * 256);
    var b = Math.floor(Math.random() * 256);
    return "rgb(" + r + "," + g + "," + b + ")";
}